Date of Award
Master of Science
Agricultural and Biosystems Engineering
Carl J. Bern
A primary problem of agricultural practice, food sufficiency, and the associated economic security for several subsistence farmers and dependent population is the lack of adequate and affordable grain storage equipments. Most previous approach to maize preservation relied on the use of chemicals. However, this research attempted to define general optimum storage conditions under different temperature, moisture and time conditions, while using a non-chemical (hermetic) approach for maize preservation.
Two studies were conducted to test the efficacy of hermetic storage system in controlling oxygen supply and maize weevil population and to test the effect of maize moisture and temperature on weevil mortality. A system was designed for the first experiment to monitor the percentage weevil mortality under hermetic conditions, over time, in both low and high moistures as well as temperature combinations. The treatment jars containing maize at two moistures (6.3 and 16%) and weevils were randomly assigned to two temperature chambers (10 and 27OC). The second experiment utilized oxygen sensors, a microcontroller and a computer running a Visual Basic 6.0 program to monitor the oxygen concentration within jars containing maize (at 8 and 16% moisture) and weevils, exposed to the two temperature chambers. Together, the two studies applied direct and indirect methods of weevil quantification
Experiment one's design consisted of four factorials (time, maize moisture, temperature, and replication), with weevil mortality being the dependent variable. Days had five levels (2nd, 4th, 6th, 8th, and 10th), maize moisture had two levels (6.3% and 16%), temperature had two levels (10OC and 27OC), and replications had four levels.
Experiment two consisted of hermetic canning jars into which ninety weevils and about 185 g of maize, at the appropriate moisture levels were loaded. The jars were randomly assigned to the temperature chambers and connected to the data acquisition system, consisting of a computer and microcontroller used for the graphic user interface (GUI) and data acquisition.
The results indicate highly significant hermetic, temperature and moisture effects on weevil mortality, and also indicate the efficacy of hermetic storage under the conditions tested.
Yakubu, Ali, "Non-chemical on-farm hermetic maize storage in East Africa" (2009). Graduate Theses and Dissertations. 10856.